Nursing Elites

1. Which of the following best describes an endothermic reaction?

• A. A reaction that absorbs heat
• B. A reaction that releases heat
• C. A reaction that does not involve heat
• D. A reaction that remains at a constant temperature

Correct answer: A

Rationale: An endothermic reaction is a process that absorbs heat from its surroundings. When a reaction absorbs heat, it leads to a decrease in the temperature of the surroundings, making choice A the correct description. In an endothermic reaction, energy is taken in from the surroundings, resulting in a decrease in temperature around the reaction site. Choice B is incorrect because a reaction that releases heat is known as an exothermic reaction. Choice C is incorrect as all reactions involve heat to some extent. Choice D is incorrect as an endothermic reaction does not remain at a constant temperature but rather absorbs heat, leading to a temperature decrease in the surroundings.

2. What are bases or alkaline solutions known as?

• A. Hydrogen acceptors
• B. Solutions of low pH
• C. Hydrogen donors
• D. Amphoteric

Correct answer: A

Rationale: Bases or alkaline solutions are known as 'hydrogen acceptors.' They accept protons (H+) in chemical reactions, as opposed to acids that donate protons. This property allows bases to neutralize acids and form salts. Choice B, 'Solutions of low pH,' is incorrect because bases have high pH values, not low. Choice C, 'Hydrogen donors,' is incorrect as bases do not donate protons but accept them. Choice D, 'Amphoteric,' refers to substances that can act as both acids and bases, which is not the definition of bases. Therefore, the correct answer is A.

3. What is an alloy in which another metal is dissolved in mercury (Hg) called?

• A. Electrum
• B. Amalgam
• C. Solder
• D. Bronze

Correct answer: B

Rationale: An amalgam is a type of alloy where another metal is dissolved in mercury (Hg). This process forms a unique mixture that has various applications in dentistry, chemistry, and other fields. Electrum is a natural alloy of gold and silver, solder is a metal alloy used to join other metals together, and bronze is a copper-tin alloy. Therefore, the correct answer is B - Amalgam.

4. What are negatively charged ions called?

• A. Neutrons
• B. Protons
• C. Anions
• D. Cations

Correct answer: C

Rationale: Negatively charged ions are called anions. Anions gain electrons and carry a negative charge, which distinguishes them from cations that are positively charged and neutrons and protons that are subatomic particles found in the nucleus of an atom. Choice A, Neutrons, are neutral subatomic particles found in the nucleus of an atom, not negatively charged ions. Choice B, Protons, are positively charged subatomic particles found in the nucleus of an atom, not negatively charged ions. Choice D, Cations, are positively charged ions that lose electrons, which is opposite to the behavior of negatively charged ions.

5. What is the correct formula for iron III oxide?

• A. IO
• B. FeS
• C. Fe₂O₃
• D. OFe₂₃

Correct answer: C

Rationale: The correct formula for iron III oxide is Fe2O3. In this formula, Fe represents iron and O represents oxygen. Iron III oxide consists of two iron (Fe) ions combined with three oxygen (O) ions. Thus, the correct formula is Fe2O3. Choice A (IO) is incorrect as it does not represent the correct combination of iron and oxygen ions. Choice B (FeS) is incorrect as it represents iron sulfide, not iron III oxide. Choice D (OFe₂₃) is incorrect as it does not follow the correct chemical nomenclature for iron III oxide.

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